I get the following error with K3B:
System locale charset is ANSI_X3.4-1968
Your system's locale charset (i.e. the charset used to encode filenames) is set to ANSI_X3.4-1968. It is highly unlikely that this has been done intentionally. Most likely the locale is not set at all. An invalid setting will result in problems when creating data projects.
Solution: To properly set the locale charset make sure the LC_* environment variables are set. Normally the distribution setup tools take care of this.

How do I change the locale charset? Google has not been my friend on this one. I figured out how to check it, but I don't really understand the output.